Hello friends I need your collective help and electrical engineering assistance please!
I have an M30T, it uses TB30 batteries. These are 5880mha capacity and run in pairs so you need to two to fly.
I have 8 of them, and a BS30 battery station.
On mains power they charge fast enough that you can fly indefinitely with only a quick landing to hotswap a pair of batteries. It’s pretty awesome!
My objective is to make this BS30 charging station mobile (think back of a pickup truck), away from mains AC power.
My question to you, is how big a portable power pack do I need?
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I think to charge 8 batteries once each I’d need 47wh of capacity? 5880 x 8?). So a 256wh battery AC unit would give me 5 full charges of 8 batteries? I think it has correct wattage power output to cope?
I hope not! It needs to be a big battery charging the little battery so that while we’re mobile the next set are charging. I’m surveying a huge area non-stop from a moving platform. The battery pack will be charging in a trailer behind us!
I would think about leisure batteries with converter hooked upto your main battery, I done it under a bonnet as I had enough room and I fitted a isolator switch so if main battery died I could turn the switch so circuit was open to allow leisure batteries to jump main battery it saved me this a few times. Its cheaper then what your looking at and generator with fuel prices. I ran fridges monitors Xbox and others on the move and parked up.
But I guess my question is, with that 110ah battery, how many recharges will I be able to put into my 8x TB30 batteries?
I’m not confident to do the math, and these are juicy big batteries I need to keep charged.
If I can calculate a setup that’ll recharge the whole set of 8 once or even twice that’ll give me 4-6 hours of flight time, which is what I need for a nights work.
Best way to calculate the real consumption is to use a plug-in power meter whilst charging the batteries indoors. That way, you will see exactly how many watts a full charge consumes. Then just divide 1300w by that figure. That will tell you how many times you can charge the batteries on a single leisure battery charge.
Based on your calc for the DJI battery consumption, 8 batteries would consume 1,248w. With Lead Acid batteries, you don’t want to discharge below 50% of the capacity, otherwise you will shorten the life of the battery considerably. So, you would need a battery that would provide at least double 1,248w. Therefore, you would need a battery with a minimum of 210Ah to safely provide a single charge for the 8 DJI batteries.
The challenge though is that anything over 130Ah tends to be 6v only. You would need 2 x 6v, 225Ah in series (for example). These can be sourced a lot cheaper if you don’t mind used. Golf buggy’s, forklift trucks … all have these batteries.
